Drill bit



Feb. 11, 1930. s. G. WOODRUFF ET AL 1,746,455

. DRILL' B11- Filed July 8, 1929 INVENTOHS SHELLEX G. WooDnuFF 'Eownnp D. .STonrs' HTTORNE Y I Patented Feb. 11, 1930 UNITED STATES PATENT OFFICE SHELLEY G. WOODRUFF, or LYNwoon, AND E WARD n. STOBTS, or LONG BEAoH,

* CALIFORNIA DRILL BIT Application filed July 8, 1929. Serial No. 376,794

.This invention relates to a drilling bit, particularly useful in the drilling of wells by the rotary process. Our invention is'an improvement upon the fish tail and the bladed type of bits, and the prime object of our invention is to provide a means whereby the bit is moved up anddown a slight amount during its rotation.

A further object is to provide a bit of the character stated which will cut more rapidly than bits heretofore in use, which issimple in construction and inexpensive to manufacture. Other objects, advantages and features of invention may appear from the accompanying drawing, the subjoined detailed descrip tion and the appended claims.

In the drawing: The figure in the drawing is a side elevation of a bit involving our invention, but with parts broken away to show interior construction.

Referring more particularly to the draw-- ing, the numeral 1 indicates the body of a bit preferably of the bladed type, the body being provided with. a plurality of cutting blades 2-3 thereon. A threaded pin 1 rises from the body 1 for the purposevof attachment between the bit and the drill pipe. A central recess 5 is provided in the body 1, and

a sleeve 6 is securely fastened to this recess.

A multi-stepped cam plate 7 is securely fastened in the sleeve 6 at the top thereof. A

pilot blade8 extends into the sleeve 6 and is.

provided with a head 9 on the top thereof, which head accurately fits the inner borevof the sleeve 6. The head 9 is provided with an upper cammed su'face 10 which fits against the cam plate 7 ,for a purpose to be further described.

A nut 11 is screwed into the bottom of the sleeve 6 for the purpose of limiting the clownward movement of the blade 8. A circulation pipe 12 extends to each of the blades 2-3 for the purpose of lubricating the bit, removing the cuttings, etc. The pipe 12 may be replaced by a duct thru the body of the bit, but the details of the water courses form no part of this invention.

In operation the bit is lowered into the hole and the pilot blade 8 first moves into the formation. There is a certain resistance, but it forms against the blade 8 which tends to' hold said blade stationary, therefore the continued rotation of the drill pipe'will cause the cam plate 7 to ride over the cams 10 on the head 9, thus raising and lowering the body 1 of the bit and imparting a striking action to the bit as it rotates and cuts. The Weight of the drill pipe is sufiicient to cause the body 1 to drop off of the cams 10 and will strike the blades 23 sharply into the formation. Having described our invention, we claim:

1. A rotary drilling bit, comprising a body, a plurality of blades on said body, a pilot blade extending below said first named blades, and means between said pilot blade and said body whereby the bod is raised and lowered during the rotation o the bit. I

2. A rotary bit comprising a body, a plu' rality of blades on said body, a pilot blade extending below said first named blades, a cam plate in said body, a head on said pilot blade, cammed surfaces on said head adapted to co-operate with said cam plate, whereby the body is raised and lowered during the rotation of the bit.

3. A rotary drilling bit comprising a body, a plurality of blades depending from said body, a pilot blade depending below said first named blades. a cam plate insaid body, a head on said pilot blade, cammed surfaces on saidhead adapted to co-operate with the cam plate and a nutscrewed into said body to limit the outward movement of said pilot blade.

4. A rotary drilling bit comprising a body, a plurality of blades depending from said body, a pilot blade depending below said first named blades, a cam plate in said body, a head on said pilot blade, oammed surfaces on said head adapted to co-operate with the cam plate and a nut screwed into said bod tolimit the outward movement of said pilot lade and circulation pipes on said body extending to each of said first named blades.

5. A rotary drilling bit comprising a body, a plurality of' blades depending from said body, a pilot blade depending below said first named "blades, a sleeve secured in the body, a cam plate-secured in the sleeve, a head on said pilot blade, said head being adapted to fit into said sleeve, cammed surfaces'on said I head adapted to oo-operate with said cam late, and a nut screwed into the sleeve wherey the outward movement of said pilot blade is limited.

6. A rotary drilling bit comprising a body, a plurality of blades on said body, a pilot blade extending below said first named blades, and means between said pilot blade 10 and said body whereby a jar is imparted to the body during the rotation of the bit.

In testimony whereof we aflix our signatures.

SHELLEY G. VVOODRUFF. 1 EDWARD D. STORTS. 

